Drill-bit-locking means.



f aired to fix the bit rigidly i the chuck, the

' the `int will nam/'e with the remainder of the tion. The Ying' isfurthermore in'oyided with an outstanding actuating head or knob 21, bywhich it inay he readily rotated. llllien the ring is in the positionshown in l? 2, nib l inay nuove outwardly, so aa to diaeng'age its innertapered end 17 from the socket or groove 18, in'nhich it may lit.llf'hen the rinij han moved around a predetermined distance. 'then thecani tace 2O will bear against the outer end ot the gib soilieicntlyltoretain the inner end in the l@aid i socket, lout the one freinent 'u'illbe so loose that the bit will have a limited Vlongitui'linal play, forwill. be noted by reference 'to Figi l that the Socket or groove 1S isconsiderably longer than the nib. It it iS def ring; is :moved Stillturnier, in which case, a bien' ia preferably struck upon the knob orlug' 2l. by come instrument so as to Wedge thd pai-ts rinly together. lnorder to maintain the ring in the first tn'o positions, asprii'ig-i'ueased nlul'iner Q52 fis 'placed in a pocket 23 'lo'iinedtianavei'sscly 'in the ring lll, and the einer end of this plunger isarranged te engage in a cnitral socket 24, or in eithei` of two sideSockets termed in the adjacent laceot' the Split 'ring l0, llfhen theiilune'er is enlfae'ld in the central Socket. as illi'istratcd inlfiifs. and :2, then the gib may be dif-:placed eniii' ly ont et thegroove lf3). "lllhen the plunger is in either et the eine Sockets Q5,then the plunge? will be, maintained in 'the `groove i8, but the bitwill Still l'u'we a limited le'ngitufflinal play.

In tl e ordinary operation ot the drill, 'the 'eine' l) may either be inthe position shown l and 2, or 'in a, position 'with the nngciq engagedin one ot the sockets Q5. if no blows t'torn the 'piston will thereforebe trai'zaniiti'cd through the tappet G to the drill in the usualmanner, and the drill bit Will he rotated.n It' new, it is desired toWiththe hit from the drill hole and the 'i ilation of cuttings behindthe point rable continue the n thercot, dui-lab' the withdrawing "'h nthe ring is positioned with the in one ot the Sockets As the paratusmoved, rearwardly, it.

nt that the inner end of the gib .i in the gro'zwe c until 'it stinkener ahonlde liereoi whereupon apparat as. The end of Said bit and thesonnet will new be in la position so that marking blows will attack by'the hammer. but tile pieton s'tl' in operae bit W l .inne herotated.It,

i, t; e drill Vat should liecon'iermly I .o nl the hole., tlm requiredto remove i t i. FingN 'is rodrill bit tirinly, pl ainel the knob 2lVwith a heavy iun'ilcn'ient. lixtra-neon?J torce may non' be applied tothc drilling' apparatus it ncccaaary to` disloi'lge the bit.

From the foregoing', 'it in thought that the construction, operation andvmany advantages oi' the herein described invention will be apparent tothose skilled in the art without t'urther deecription. and it will be undci'stood that various changes in the size, sha ne'pii'qioition andminor details ot construction may bc resorted to Without departN inn''from the spirit or ,Qacriiicing any ot the advantages of the invention.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is:-

l. In a rock drill, the combination with a bit-'receivingchuck, of a bitthat engagea therein, and means mounted on the chuck and slidablvinterlocking with the bit for holding Said bit in the chuck againatdetachment While permitting a limited longitudinal movement ot the Samein the chuck,

said means alc-o l 'c' capable ol" fixed cngagcinent with t..e hit toi'Sccurii'ig' ,auch bit lixcdly against longitudinal rn'iovcufient in thechuck.

'2. In a rock drill,y the combination with a hit-rcceiving chuck, of rahit tha, detachably and slidably engagea therein. and coininen meansnionntcd on the chuck and dctachaloly interlocking with the bit loi'securing said bit in the chuck While permit ting a limited longitudinalplay thereof and 'for securing said bit txcdly against move nient insaid chuck.

3. In a rock drill, the combination with a bit-receiving chuck, oll .qbit that slidably and dctachably'e'agaggcs therein, common means mountedon the chuck and detachably interlocking with the bit 'for securing Saidoit in the chuck while permitting a limited longitudinal play thereofand for securing Said bit .fixcdly against movement 'in said chuclnyandmoana 'tor mainl'ainimg1r the holdingr means in the toi'inci el its aaidpositions.

4. In a rock drill, the combination with a bit-receiifinggchuck, oll abit that alidably and detachably engages therein, Said bit. havingr anelongated socket.y a gilicairiod by ll the chuck and movable into andout of the socket, said `gib being of leas length than thesocket. andnieane` :For holdingthe gil) loosely and also tightly in the socket, toifcspectiyely permit and prevent limited longitudinal play ot' the bitin the chuck,

5. In a 'rock drill, the combination with a bitmeceiving chuck, oi a bitthat alidably and -lc'tachaiily therein, said bit having' an elongatedeocket, a 1aib carried by the chuck and movable into and out of thesocket, iid `n'ib being ol less length than the aocli'et, means forholding the gib

